1. The Universe

2. A. The Universe Only one exists
Composed of space and 100 billion galaxies
A galaxy is a grouping of millions or billions of stars kept together by gravity

3. How did the universe begin?
The current understanding of the how the universe began is described by the Big Bang Theory—it wasn’t big and there wasn’t a bang!

4. Formation of the Universe
Big Bang Theory: Explains how universe developed from very tiny, dense “singularity”

5. More on the Big Bang Theory
The theory states: the universe began from an initial point (or singularity) which has expanded over billions of years to form the universe as we now know it today.

6. Formation of the Universe
Big Bang Theory: According to BBT, UNIVERSE is 13.7 Billion years old

7. Formation of the Universe
Big Bang Theory: Does NOT explain what initiated creation of universe
Only describes expansion of universe

8. 4. Edwin Hubble (in 1929) proposed that the Universe is expanding
a. This is supported by a phenomenon called the Doppler shift
1). Stars are moving away from Earth and their light becomes dimmer. This is called the red shift. This gives support of the expanding universe
2). If stars move toward Earth, we see a blue shift – light becomes brighter

9. Putting it Together… Inversely Proportional:
Wavelength increases = Frequency decreases

10. Universe is EXPANDING
Doppler Effect: – Change in frequency of waves moving relative to its source
Stars moving AWAY = RED shift
Stars moving TOWARD = BLUE shift
Greater the shift = faster the speed

12. Evidences? Universe is EXPANDING
Cosmic Background Radiation – Low temp waves indicating explosion occurred
Gravity – Responsible for movement of dust clouds to form planets and stars

16. B. Galaxies Galaxies are classified according to their shape
Spiral galaxies often appear bluish because they contain many young stars
a. Young stars give off blue light when they burn
Elliptical galaxies often appear reddish because they contain many old stars
a. Old stars give off red light when they burn

17. Galaxies, cont. A large cluster of galaxies is called a supercluster
Our solar system is inside the galaxy known as the Milky Way
a. The Milky Way is classified as a spiral galaxy
The Milky Way contains interstellar matter that may form new stars

18. Elliptical

19. Spiral Galaxies

20. Milky Way Galaxy
Top View
Side View

21. C. The Solar System
Copernicus ( ) first proposed that Earth and the other planets orbit the sun
The orbits of the planet were first said to be elliptical by Kepler ( )
The brightest object in our sky (besides the sun and the moon) is Venus

22. Nickolas Copernicus

23. Formation of Solar System
Nebular Theory: SOLAR SYSTEM formed from huge, rotating cloud disk of dust and gases

24. Our solar system is approximately 4.6 billion years old.
5. The most widely accepted model of the formation of the solar system is the nebular model where the solar system condensed out of a nebula – a huge cloud of interstellar gas and dust
i. Planets may have formed out of material orbiting the early sun through the process of accretion where small particles collide and stick together to form larger masses
ii. Gaseous clouds—nebulae, which slowly rotate, gradually collapse and flatten due to gravity and eventually form stars and planets.
Our solar system is approximately
4.6 billion years old.

25. What is the difference between the Solar System, Galaxy, and Universe?
Basically SIZE is the biggest distinction.
We live on planet Earth which is part of our local Solar System.
Our Solar System includes the Sun and everything that orbits the Sun.
Our Sun, is just one Star in the Milky Way Galaxy.
The Milky Way Galaxy is just one Galaxy in the Universe.

26. KEPLER
HELIOCENTRIC MODEL
3 LAWS OF PLANETARY MOTION

27. Orbit of every planet is an ellipse with Sun at one foci (focus)
Kepler’s First Law
Orbit of every planet is an ellipse with Sun at one foci (focus)

28. Kepler’s Second Law
Planet moves fastest when closest to Sun and slowest when farthest from Sun
Equal areas are swept out in equal amount of time

29. Kepler’s Third Law
Compares distance of each planet from Sun and its orbital period around Sun

30. The order of the planets are Mercury, Venus, Earth, Mars, and
Jupiter, Saturn, Uranus, and Neptune.

31. What’s the Difference?
SIZE and COMPSITION

32. Terrestrial Planets Inner 4 Planets: Mercury Venus Earth Mars
Small, solid, rocky surfaces

33. Jovian Planets Outer 4 Planets: Jupiter Saturn Uranus Neptune
Larger, gaseous, and lacks solid surfaces

35. Earth Facts Distance to Sun: ~92,000,000 Million miles
Age of Earth: ~4.6 Billion Years
Size: 5th largest in solar system

36. i.Mercury is closest to the sun and has very hot temperatures
ii.The inner planets and outer planets are separated by an asteroid belt
iii. The great red spot on Jupiter is believed to be a giant storm
iv. All of the gaseous outer planets have rings